This disclosure relates generally to optoelectronic devices and more particularly to a light emitting diode (LED) device having a lens protective structure, and to a method for fabricating the (LED) device.
As shown in FIG. 1, a prior art light emitting diode (LED) device 10 includes a substrate 12, a (LED) die 14 electrically connected to the substrate 12 via a wire bonded wire 16, and a lens 18 covering the (LED) die 14. The lens 18 can comprise a transparent material deposited on the substrate 12, or a separate member bonded to the substrate 12. Typical materials for the lens 18 include silicone, epoxy and glass.
As also shown in FIG. 1, a bonding layer 20 can be used to attach the lens 18 to the substrate 12, and to seal the (LED) die 14 on the substrate 12. The bonding layer 20 can comprise a polymer (e.g., silicone, epoxy), a glass frit or a non-conductive adhesive film (NCF). The bonding layer 20 is bombarded by direct electromagnetic radiation 22 from the (LED) die 14 and by reflected electromagnetic radiation 24 from the lens 18. This electromagnetic radiation 22, 24 can damage the bonding layer 20 causing delamination of the lens 18 and attendant seal. Depending on the lens material, the electromagnetic radiation 22, 24 can also damage the lens 18 by yellowing or hazing. Electromagnetic radiation 22, 24 in the ultraviolet (UV) spectrum is particularly damaging to bonding layers 20 made of polymer materials. This damage can compromise the performance of the (LED) device 10, and in some cases can effectively render the (LED) device 10 as useless.
The present disclosure is directed to a light emitting diode (LED) device having a lens protective structure configured to protect the lens and a lens bonding layer from damage due to electromagnetic radiation. In addition, the lens protective structure is configured to reflect electromagnetic radiation increasing light extraction from the (LED) device. The present disclosure also provides a method for fabricating the light emitting diode (LED) device with the lens protective structure.